1. Field of the Invention
The present invention relates to a wet-type image forming apparatus for forming a toner image using a liquid developer.
2. Description of the Related Art
There is known a wet-type image forming apparatus for forming a toner image using a liquid developer. The wet-type image forming apparatus includes an image carrying member on which a toner image is to be formed, a developing device for supplying a liquid developer to the image carrying member to form a toner image on the image carrying member, a liquid developer supplying device for supplying the liquid developer to the developing device, a transfer unit for transferring the toner image on the image carrying member onto a sheet, and a fixing unit for fixing the toner image on the sheet to the sheet.
The liquid developer has a high viscosity since toner as a solid content is dispersed in a dielectric liquid as a carrier. To obtain a high-quality toner image using a liquid developer having a high viscosity, the liquid developer supplying device needs to form a liquid developer layer with a uniform thickness on the circumferential surface of a developing roller when supplying the liquid developer to the developing roller of the developing device.
The following related art is known as a technology meeting such a request. In this related art, a liquid developer supplying device used in a wet-type image forming apparatus is such that two discharge ports are arranged side by side in a circumferential direction of a developing roller and are slits extending in an axial direction of the developing roller, and a liquid developer is discharged onto the circumferential surface of the developing roller via these discharge ports to form a liquid developer layer with a uniform thickness on the circumferential surface.
However, in the image forming apparatus of the related art, the liquid developer may leak from the discharge ports of the liquid developer supplying device due to an impact or vibration produced when the developing device is detached from an apparatus main body of the image forming apparatus, for example, for maintenance of the developing device. If the liquid developer leaks to the outside, the interior of the apparatus main body is contaminated. If the running down or dripping liquid developer adheres to the hand of a maintenance operator, a maintenance operation is disrupted.
If a developing operation is not performed for a long time, the toner as the solid content in the liquid developer settles down in the liquid developer supplying device. Thus, when a new developing operation is performed, inconveniences such as a reduction in toner supply amount and a discharge failure are likely to occur. This makes it difficult to form a liquid developer layer with a uniform thickness on the circumferential surface of the developing roller.